Doug,
I am a firm believer in a static dissipative flooring and using ESD shoes
to connect the personnel.
Having experience with ESD vinyl tiles, carpeting, and coatings, I have
found that the most economical method is to put down whatever flooring that
is acceptable to the management looks wise. After the flooring is down,
then apply a high quality ESD static dissipative floor coating. I agree
with Paul that the ground strap is essential and I prefer to see multiple
earth ground rods connected to the ESD ground system/flooring. Next make
sure you have a janitorial service set up so that the coating is maintained
with regular frequency. Test your coating regularly and use the results to
instruct the janitorial staff when the coating needs to be stripped off and
re-applied. We aim for six months between applications. We do weekly wet
mopping where the higher traffic areas are as well.
As far as the concrete is concerned, we have several warehouse areas which
do not have floor tile and the interesting fact is that these areas
marginally pass our testing without even being coated with the ESD floor
coating. We attribute this to the release compounds applied to the
concrete when the buildings were fabricated (tilt up walls). However, we
do apply the coating to the sealed concrete and it performs just like the
areas that are tiled.
Ourcoating test results are approx 0.5-1 megohm initially gradually degrade
up to 100 megohm at which time we notify the janitorial staff. By the time
the floor is re-coated, it will not have exceeded the 1000 megohm maximum
limit. Results of 10 megohm are typical of all areas. We use the EIA 625
specification for our testing methodology.
The opponents of the floor coatings cannot deny that you need to have a
janitorial service because we all want to work in a clean environment, so
the beauty of this method is that all you have to do is switch the
materials and do a little testing.
Phil
At 01:09 PM 10/9/99 +1000, Paul Klasek wrote:
>"CONDUCTIVE" is used only in ammunition and fireworks factories, explosive
>compounds generally ;
>otherwise with powered equipment on the floor it can kill .
>Dissipative vinyl would be best way to go ;
>The self dissipating(with some humidity in the air) paint on concrete does
>not last in traffic spots more than couple of months .
>Bare concrete is neutral, but dusty; sealed with epoxy is static generating
>, not dissipating .
>Doug, the archives are full of ESDAssociation references ;
>which I'd find more practical than BS or DIN,
>you can get them on disk as well .
>
>Repeating myself again : make sure you have 1Mohm resistor somewhere between
>ground and grounded .
>There is a legal difference between conductive and dissipative surface when
>it comes to accidents ;
>and even ESDA standards underline the safety as a logical PRIORITY:
>for example whereas SSteel cabinet covers are normally grounded direct ;
>in instances of working with power equipment for example on SSteel bench ;
>that bench should be grounded indirect (with resistor in the path) .
>
>ESD's grounding does have similar character as CO2 versus CO ;
>TOO simple and common perceptions can be deadly in certain circumstances
>without lateral thought .
>Similar to those having gas heaters not flued outside .
>
>Get the standards Doug, they're absolutely essential;
>this is one of few fields where "common sense" is not desirable .
>
>
>Paul Klasek
>ResMed
>
>-----Original Message-----
>From: Doug [mailto:[log in to unmask]]
>Sent: Friday, 8 October 1999 17:14
>To: [log in to unmask]
>Subject: [TN] Conductive Floors ...
>
>
>What's the actual resistance of a floor that's
>considered acceptably "conductive" for an area
>that will be handling telecommunication boards?
>I mean, if a customer came into your facility
>and wanted to measure your floor to have it pass
>or fail being a suitably "conductive", what
>resistance would they use for that criteria?
>
>A former coworker informed me that my old company
>is moving to their new building. With the move
>is the discussion about whether to leave the new
>area as bare concrete, tile it, or paint it.
>I'm of the opinion that they can leave it as bare
>concrete, but that's only my opinion.
>
>The old building had conductive tile with copper
>strips and was extremely expensive but reliable.
>It also seemed to make the customers feel at ease
>with something they could see as opposed to bare
>concrete. I can remember making periodic checks
>with a surface resistance tester, but for the life
>of me, I can't remember the limits.
>
>Any additional comments or opinions appreciated,
>since this topic seems to come up here every now
>and then.
>
>Regards, Doug
>
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